Is your
knot meter working? Are you showing at least 0.0? If not, I don't think it can caculate true, so you get ---. If it is not showing, you might try looking at the connections on the back of the instrument. Make certain there is no
corrosion. When you remove them to check, you'll have to cycle the instruments off and on to get the transponder to register with the dept gauge.
Good Luck.
Keith